316 ANNUAL OP SCIENTIFIC DISCOVERY. 



feet in height, showing the thickness of the vein or stratum from 

 which they are taken. 5. A specimen of coal, weighing about eleven (11) 

 tons, taken from the thirty-foot seam, showing the fracture of the coal, 

 and its pure and excellent quality. 



COAL FIELDS OF MARYLAND. 



Dr. Higgins, State agricultural chemist, reports fifteen veins in the great 

 coal region of Alleghany county, Maryland, many of which, however, 

 have no economical value, as it would cost more to w r ork them than the 

 product would justify. The chief veins are first, the two-feet vein ; 

 second, the three-feet vein ; third, the forty-inch vein ; fourth, the six-feet 

 vein ; fifth, the eight-feet vein ; sixth, the big, or fifteen-feet vein. The 

 most important veins, however, and those now worked for exportation, are 

 the big vein, the six-feet vein, and the forty-inch vein. The big vein is 

 considered the most valuable ; it contains an average thickness of eleven 

 feet of workable coal. It is estimated that there are in this field 20,000 

 acres of workable big- vein coal, 80,000 acres of six-feet vein, and 80,000 

 acres of the forty-inch vein. It will thus be seen that the smaller veins 

 embrace a much larger area than the big vein. They do not suffer so 

 much by denudations. 



ON THE CHARACTERISTICS OF THE CARBONIFEROUS FLORA OF 



OHIO. 



At the American Scientific Association, Cleveland, Dr. J. S. Newberry, 

 in a communication on the above subject, said that he had made a com- 

 parison of the coal plants of Pennsylvania and such as had already been 

 collected in Ohio, and had been surprised to find so great a discrepancy. 

 Of the species collected, scarcely one in ten were common to the two 

 States. This difference was due partly to the geographical distribution of 

 species which in former epochs, as now, gave to different districts some- 

 what different floras, but more to the changes which had been effected in 

 the flora of the same surface during the deposition of the different car- 

 boniferous strata, giving to the upper beds of coal a very different cata- 

 logue of plants from that of the lower ones. In Pennsylvania, the prox- 

 imity of igneous rocks had nearly obliterated the vegetable impressions 

 from the roof stone of the lower beds ; consequently most of the speci- 

 mens from that State had been collected from the upper beds ; while 

 in Ohio the largest collection had been made from the lowest bed in the 

 series, where the flora was much the richest. 



The shales and sandstones associated with the lowest stratum of coal in 

 Northern Ohio furnish a greater variety of fossil plants than has, per- 

 haps, ever been found elsewhere within equal geographical and geological 

 limits. 



In Europe, rarely more than thirty or forty species accompany a single 



